Adsorbents for low vapor pressure fluid storage and delivery

ABSTRACT

The invention relates to a fluid storage and delivery system utilizing a porous metal matrix that comprises at least one Group VIII metal or Group IB metal therein. In one aspect of the invention, such porous metal matrix forms a solid-phase metal adsorbent medium, characterized by an average pore diameter of from about 0.5 nm to about 2.0 nm and a porosity of from about 10% to about 30%. Such solid-phase metal adsorbent medium is particularly useful for sorptively storing and desoprotively dispensing a low vapor pressure fluid, e.g., ClF 3 , HF, GeF 4 , Br 2 , etc. In another aspect of the invention, such porous metal matrix forms a solid-phase metal sorbent, characterized by an average pore diameter of from about 0.25 μm to about 500 μm and a porosity of from about 15% to about 95%, which can effectively immobilize low vapor pressure liquefied gas.

BACKGROUND OF INVENTION

1. Field of Invention

The invention relates to a fluid supply systems, to a solid-phaseadsorbent material useful for storing and dispensing fluids of low vaporpressure, and to a solid-phase sorbent material useful for storing anddispensing liquefied fluids.

2. Description of the Related Art

In a wide variety of industrial processes and applications, there is aneed for a reliable source of process fluids. Such process andapplication areas include, but are not limited to, semiconductormanufacturing, ion implantation, manufacture of flat panel displays,medical intervention and therapy, water treatment, emergency breathingequipment, welding operations, space-based delivery of liquids andgases, etc.

Conventionally, processing fluids are supplied for commercialapplications by means of high-pressure cylinders containing compressedprocessing fluids. However, such conventional high-pressure gascylinders are susceptible to leakage from damaged or malfunctioningregulator assemblies, as well as to rupture if internal decomposition ofthe gas leads to rapid increase of interior gas pressure in thecylinder. These deficiencies pose a risk of unwanted bulk release of gasfrom the cylinder. Such bulk release in turn can create very hazardousand even catastrophic conditions where toxic or otherwise hazardousfluids are involved, particularly during transportation and shipment offluid cylinders when back-up scrubbing or other safety systems may notbe present.

To overcome these inherent problems of high-pressure gas cylinders,sorbent-based fluid storage and dispensing systems may be employed, ofthe type disclosed in U.S. Pat. No. 5,518,528, issued May 21, 1996 inthe names of Glenn M. Tom and James V. McManus. Such sorbent-based fluidstorage and dispensing systems effectively reduce the interior gaspressure by reversibly adsorbing sorbate fluid onto a physical sorbentmedium disposed inside a containment vessel.

Sorbent-based fluid storage and dispensing systems of such typesignificantly reduce the risk of gas leakage and cylinder ruptureassociated with conventional high-pressure gas cylinders. These systemstypically utilize physical sorbent materials, such as silica, carbonmolecular sieves, alumina, polymers, kieselguhr, carbon, andaluminosilicates, having average pore sizes in a range of from 4Angstroms to 13 Angstroms. Although these sorbent materials of such poresize character are effective for reducing pressure of certain high vaporpressure fluids (e.g., AsH₃, PH₃, and BF₃), they are not satisfactoryfor purpose of storing and delivering fluids of low vapor pressures(i.e. <200 psig at room temperature), especially the reactive fluids,for the following reasons.

First, such sorbent materials are chemically incompatible with low vaporpressure gases such as ClF₃, WF₆ and Br₂, reacting with the gases toform unwanted byproducts.

Further, such conventionally employed sorbent materials, due to theirrespective pore size distributions, are oftentimes characterized byadsorption potentials that are too high. They cannot effectively desorblow vapor pressure gases from the sorbent, and therefore are inadequateto deliver low vapor pressure gases to the tool under normal applicationconditions. The term “normal application conditions” is hereby definedas fluid delivery conditions characterized by a decrease of pressurefrom 650 torr to 10 torr at room temperature.

For example, sorbent materials of the type disclosed by the Tom et al.patent, which are characterized by (1) average pore sizes in the rangeof 4-13 Angstroms and (2) porosity in the range of 30-40%, measured as[gross volume of sorbate/gross volume of sorbent material includingvoids]×100%, are only able to desorb 10-20% of the low vapor pressuregases such as Br₂ under normal application conditions, while the samesorbent materials can desorb 70-90% of the high vapor pressure gasessuch as arsine (AsH₃) and phosphine (PH₃). U.S. Pat. No. 6,089,027,issued Jul. 18, 2000 in the names of Luping Wang and Glenn M. Tom,describes an improved gas storage and dispensing system for storage anddispensing of low vapor pressure liquefied gases such as ClF₃, WF₆,GeF₄, and Br₂, etc., in which a fluid pressure regulator is disposedinside of the fluid storage and dispensing vessel. The fluid pressureregulator functions as a flow control device, which can be set at apredetermined pressure level, to dispense fluids from the vessel at suchpressure level. Such “regulator in a bottle” arrangement provides aneffective system for storage and dispensing of liquids and gases atpressure levels that vary from about 50 psig to about 5000 psig,depending on the specific end use application. When the pressure is setat a subatmospheric level, it can effectively eliminate the hazards ofgas leaking out of the vessel in case of development of an external leakduring cylinder transportation. The “regulator in a bottle” arrangementis also ideal for safe storage and delivery of very low vapor pressure(less than 14.7 psia) pyrophoric organometalllic fluids such astrimethyl aluminum, dimethyl aluminum hydride, etc. When storingpyrophoric fluids of very low vapor pressure, the “regulator in abottle” arrangement with the subatmospherical setting can effectivelyprevent air from leaking into the cylinder if an external leak developsduring cylinder transportation and handling, therefore eliminating thepotential fire and other hazards caused by reaction between thepyrophoric fluids and the air.

However, when the fluid storage and dispensing vessel of Wang et al.patent is used for liquefied gases, the fluid pressure regulator issusceptible to malfunction, because liquefied gases can easily enter theregulator and cause discharge pressure instability. In applications suchas semiconductor manufacture, the maintenance of precisely controlledflow characteristics (temperature, pressure, flow rate and composition)is critical to the achievement of satisfactory product microelectronicdevice structures. In such applications, the pressure instabilityincident to liquid ingress to the regulator compartment causes theoccurrence of process perturbations that may render the productmicroelectronic device structure unsatisfactory or even wholly uselessfor its intended purpose.

Moreover, during the fluid delivery process significant cooling occurswhen the liquefied gas is evaporated from the storage cylinder, due tothe heat loss of vaporization. The cooling will significantly reduce thevapor pressure of the liquefied gas, resulting in insufficientevaporation and slowing down gas flow from the cylinder. One or moreheat-exchange units are usually provided on the external wall of thecylinder, for externally supplying thermal energy to the liquefied gasto compensate for the heat loss caused by evaporation. However, theconventional sorbent materials have low thermal conductivities and aretherefore ineffective for transfering heat to the liquefied gas insidethe cylinder. Insufficient heat transfer causes uneven distribution ofthermal energy in different portions of the cylinder, i.e., overheatingof the exterior of the cylinder and underheating of the interior of thecylinder.

The art has not found a solution to the above-described problemsassociated with low vapor pressure fluids or liquefied gases, withrespect to sorbent materials having good sorptive affinity, goodcapacity loading characteristics, good chemical stability, gooddesorption characteristics, good thermal conductivity, or of liquidcontainment and occlusion from the regulator element in internalregulator-based fluid storage and dispensing systems.

There is accordingly a need in the art for a physical sorbent materialthat is chemically compatible with low vapor pressure fluids, that hasan adequate pore size, porosity and pore size distribution to reducestorage pressure of low vapor pressure gases via reversible adsorptionof such gases, and that enables the sorbate fluid to be readily desorbedfrom the physical adsorbent material for discharge from the vesselduring dispensing operation.

There is concurrently a need in the art for a solution for the liquidingress problems associated with the use of internal regulator-basedfluid storage and dispensing systems.

SUMMARY OF THE INVENTION

The present invention resolves the aforementioned problems by the use ofa solid-phase sorbent medium for storing and dispensing a low vaporpressure fluid, in which such solid-phase sorbent medium can effectivelydesorb the low vapor pressure fluid therefrom under normal applicationconditions. Further, the present invention is useful for storing anddispensing a liquefied gas, in which such solid-phase sorbent mediumfunctions as a protective medium to prevent the liquefied gas fromentering into the regulator element in an internal regulator-based fluidstorage and dispensing system.

The solid-phase sorbent medium of the present invention is a porousmetal matrix comprising at least one, Group VIII or IB metal or metalalloy.

The porous metal matrix may comprise any Group VIII or IB metal or metalalloy that is chemically compatible with the low vapor pressure fluid,accommodating the sorption and desorption of the fluid without adversereaction or other interaction. The porous metal matrix thus may comprisemetals selected from the group consisting of iron, nickel, cobalt,ruthenium, rhodium, palladium, osmium, iridium, platinum, copper,silver, gold and alloys, blends and combinations of one or more of theforegoing metal species.

The term “low vapor pressure”, when used herein, means vapor pressure ofless than 200 psig, measured at room temperature. Low vapor pressurefluids of particular interest in the general practice of the inventioninclude, but are not limited to, ClF₃, WF₆, HF, GeF₄, Br₂, and the like.

Among Group VIII metals, nickel and iron have been discovered to beparticularly compatible with low vapor pressure fluids and therefore arehighly advantageous materials for forming the porous metal matrix. In aparticularly preferred embodiment of the present invention, stainlesssteel is used as a material of construction for the porous metal matrix.

In one aspect of the invention, the porous metal matrix constitutes asolid-phase metal adsorbent medium for adsorbing low vapor pressureliquids, having (1) an average pore diameter in the range of from about0.5 nm to about 2.0 nm and (2) a porosity in the range of from about 10%to about 30%. The pore size distribution of such solid-phase metaladsorbent medium is preferably characterized by about 80% to about 90%of pores having a diameter in the range of from about 1.5 nm to about2.0 nm, and about 10% to about 20% of pores having a diameter greaterthan 2.0 nm.

The solid-phase metal adsorbent medium of the invention, as describedhereinabove, is capable of reducing the pressure of low vapor pressurefluids to subatmospheric pressure levels on the order of 12.6 psia/0.85atm.

Such solid-phase metal adsorbent medium may also contain non-metaladsorbent particles that are dispersed in a porous Group VIII or GroupIB metal matrix, or alternatively, such solid-phase metal adsorbentmedium may comprise non-metal adsorbent particles that are coated withGroup VIII or IB metal(s) or metal alloy(s). Useful non-metal adsorbentparticles in practice of the present invention include, but are notlimited to, zeolites, carbon materials, porous silicon. polymers,aluminum phosphosilicate, clays, and combinations of two or morethereof. Among these non-metal adsorbent materials, zeolites and carbonmaterials, or combinations thereof, are preferred. Preferably, theaverage pore size of the non-metal adsorbent particles is less than 500μm and more preferably in a range of from about 0.5 nm to about 50.0 nm.

In another aspect of the invention, the porous metal matrix constitutesa solid-phase metal sorbent medium for containing and immobilizingliquefied gases in an internal regulator-based fluid storage anddispensing system, having (1) an average pore diameter in a range offrom about 0.25 μm to about 500 μm and (2) a porosity in a range of fromabout 15% to about 95%. The solid-phase metal sorbent medium in thisembodiment is particularly effective for immobilizing the liquefiedgases and preventing such gases from entering into the fluid pressureregulator and iterfering with its proper operation.

Yet another aspect of the present invention relates to a process offorming the porous metal matrix, comprising the steps of:

providing fine metal particles of at least one of Group VIII metals,Group IB metals, and alloys thereof, and

sintering such fine metal particles, e.g., in a sintering furnace, toform the porous metal matrix.

The term “fine metal particles” as used herein means metal particleshaving an average particle size of not more than about 1000 μm andpreferably not more than about 500 μm. More preferably, the fine metalparticles used in the practice of the present invention have an averageparticle size in the range from about 20 nm to about 1 μm.

Sintering of the fine metal particles may be carried out in a sinteringfurnace or in other suitable manner, at an appropriate temperature,e.g., a temperature in a range of from about 20° C. to about 1500° C.,to ensure formation of a continuous metal matrix without destroying theporosity of the fine metal particles being sintered.

In a still further aspect of the present invention, the porous metalmatrix is formed by a process comprising the steps of:

forming a solid-phase matrix comprising at least one Group VIII or IBmetal and an oxidizable carbon-containing material; and

heating such solid-phase matrix in the presence of an oxidizing agent togasify the oxidizable carbon-containing material.

Oxidizable carbon-containing materials useful in the practice of thepresent invention include, but are not limited to, elemental carbonmaterials, such as graphite, diamond, amorphous carbon, etc., as well asvarious hydrocarbon compounds. Preferably, the oxidizablecarbon-containing materials comprise hydrocarbon compounds. However,such preference is not intended to limit the broad practice of thepresent invention. One ordinarily skilled in the art can readilydetermine, without undue experimentation, other suitable species ofcarbon-containing materials for the purpose of practicing the presentinvention, according to specific operational requirements andconditions.

The oxidizing agent useful in the practice of the present invention mayinclude any suitable oxidizer commonly used and well-known in the art.In one preferred embodiment, such oxidizing agent is selected from thegroup consisting of elemental oxygen, oxygen gas (O₂), ozone, air, andcombinations thereof. Other kinds of oxidizers can also or alternativelybe employed, as will be readily determinable by one ordinarily skilledin the art.

In another specific aspect of the present invention, the porous metalmatrix is formed by a process including the following steps:

forming a solid-phase matrix comprising at least one Group VIII or IBmetal and soluble metal oxide particles; and

immersing such solid-phase matrix in an acidic solution to dissolve saidsoluble metal oxide particles.

The term “soluble metal oxide”, as used herein, means a metal oxidedissolvable in an acidic solution.

Preferably, the soluble metal oxide particles comprise at least onemetal component selected from the group consisting of Fe, Ni, Ag, andPt. The soluble metal oxide particles can be of any suitable particlesize and particle size distribution characteristics.

Another aspect of the present invention relates to anadsorption-desorption apparatus, for storage and dispensing of a lowvapor pressure fluid, comprising:

a storage and dispensing vessel constructed and arranged for holding asolid-phase metal adsorbent medium;

a solid-phase metal adsorbent medium disposed in said storage anddispensing vessel at an interior gas pressure, said solid-phase metaladsorbent medium comprising a porous metal matrix including at least oneGroup VIII or IB metal;

a low vapor pressure fluid adsorbed on said solid-phase metal adsorbentmedium; and

a dispensing assembly coupled in gas flow communication with the storageand dispensing vessel, and arranged for dispensing from the vessel thelow vapor pressure fluid desorbed from the solid-phase metal adsorbentmedium.

A further aspect of the invention relates to a fluid storage anddispensing system, comprising a vessel holding a solid-phase metaladsorbent medium having a low vapor pressure fluid adsorbed thereon,such vessel including a port having dispensing means associatedtherewith for controllably dispensing the low vapor pressure fluiddesorbed from the solid-phase metal adsorbent medium in a dispensingmode of operation of the system, wherein the solid-phase metal adsorbentmedium includes a porous metal matrix comprising at least one Group VIIIor IB metal.

Such solid-phase metal adsorbent medium preferably has (1) an averagepore diameter in a range of from about 0.5 nm to about 2 nm, and (2) aporosity in a range of from about 10% to about 30%.

Exclusive of the solid-phase metal adsorbent medium of the presentinvention, such adsorption-desorption apparatus may be of a general typedescribed in U.S. Pat. No. 5,518,528 for “Storage and delivery systemfor gaseous hydride, halide, and organometallic group V compounds,”issued May 21, 1996 to Glenn M. Tom and James V. McManus, the disclosureof which is incorporated by reference herein in its entirety.

Yet another aspect of the present invention relates to a fluid storageand dispensing apparatus, for storage and dispensing of a low vaporpressure liquefied gas, comprising:

a storage and dispensing vessel constructed and arranged for holding asolid-phase metal sorbent medium;

a solid-phase metal sorbent medium disposed in said storage anddispensing vessel at an interior gas pressure, said solid-phase metalsorbent medium comprising a porous metal matrix including at least oneGroup VIII or IB metal;

a low vapor pressure liquefied gas sorbed by said solid-phase metalsorbent medium;

a fluid dispensing assembly coupled in gas flow communication with thestorage and dispensing vessel, and arranged for dispensing from thevessel gas derived from the low vapor pressure liquefied gas; and

a fluid pressure regulator associated with the fluid dispensingassembly, and arranged to maintain a predetermined pressure in theinterior volume of the vessel,

wherein the fluid dispensing assembly is selectively actuatable to flowgas, derived from the low vapor pressure liquefied gas sorbed by saidsolid-phase metal sorbent medium, through the fluid pressure regulator,for discharge of the gas from the vessel.

Preferably, such metal sorbent medium for sorbing the low vapor pressureliquefied gas is characterazed by (1) an average pore diameter in arange of from about 0.25 μm to about 500 μm and (2) a porosity in arange of from about 15% to about 95%.

More preferably, the fluid storage and dispensing apparatus of thepresent invention further comprises one or more heating elements forsupplying thermal energy to compensate for heat loss during theevaporation of the low vapor pressure liquefied gas. Such heatingelements may be constructed and arranged in any manner to supply thermalenergy to the low vapor pressure liquiefied gas. For example, suchheating elements may be dispersed among the sorbent medium inside thestorage and dispensing vessel; alternatively, such heating elements maybe disposed on an external wall of the storage and dispensing vessel andsupply thermal energy to the liquefied gas through thermal conduction.The solid-phase metal sorbent medium preferably has high thermalconductivity for effectively conducting the thermal energy from theexternal wall of the storage and dispensing vessel to the liquefied gasstored therein.

Exclusive of the solid-phase metal sorbent medium of the presentinvention, such fluid storage and dispensing apparatus may be of ageneral type described in U.S. Pat. No. 6,089,027 for “Fluid storage anddispensing system,” issued Jul. 18, 2000 to Luping Wang and Glenn M.Tom, the disclosure of which is incorporated by reference herein.

Yet another aspect of the present invention relates to a process forsupplying a low vapor pressure fluid reagent, comprising:

providing a storage and dispensing vessel containing a solid-phase metaladsorbent medium having a sorptive affinity for said low vapor pressurefluid reagent;

sorptively adsorbing the low vapor pressure fluid reagent on thesolid-phase metal adsorbent medium at an interior gas pressure to yielda sorbate fluid-retaining metal adsorbent medium;

desorbing sorbate fluid from the sorbate fluid-retaining metal adsorbentmedium; and

dispensing the desorbed fluid from said storage and dispensing vessel;

wherein the solid-phase metal adsorbent medium comprises a porous metalmatrix including at least one Group VIII or IB metal.

In a still further aspect, the invention relates to a method ofsupplying a low vapor pressure fluid to a process requiring same, suchmethod comprising sorptively retaining the low vapor pressure fluid on asolid-phase adsorbent including a porous metal matrix comprising atleast one Group VIII or IB metal, and desorptively removing the lowvapor pressure fluid from the adsorbent and transporting same to theprocess when the process requires same.

Yet another aspect of the invention relates to a method of suppressingpressure perturbations of a fluid storage and dispensing systemincluding a storage and dispensing vessel for holding a low vaporpressure liquefied gas therein, a discharge assembly disposed on thevessel for dispensing the low vapor pressure liquefied gas therefrom,and a gas flow regulator inside the vessel arranged for flowtherethrough of gas deriving from the low vapor pressure liquefied gas,so that gas flows through the regulator prior to flow through thedischarge assembly, wherein the pressure perturbations are occasioned byingress of the low vapor pressure liquefied gas into the regulator, suchmethod comprising shielding the regulator from contact with the lowvapor pressure liquefied gas with a body of solid-phase metal sorbentmedium arranged in the vessel to sorptively immobilize any low vaporpressure liquefied gas that would otherwise flow into the regulator,such metal sorbent medium including a porous metal matrix comprising atleast one Group VIII or IB metal. Preferably, such metal sorbent mediumis characterazed by (1) an average pore diameter in a range of fromabout 0.25 μm to about 500 μm and (2) a porosity in a range of fromabout 15% to about 95%.

Other objects and advantages of the invention will be more fullyapparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an adsorption-desorption apparatusaccording to one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional elevation view of a fluid storageand dispensing system according to another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED EMBODIMENT THEREOF

The present invention relates to an improved sorbent material forstorage and dispensing of low vapor pressure fluids, comprising a porousmetal matrix including one or more Group VIII metals. The metal(s) maybe in elemental or alloyed forms, and where multiple metal componentsare present, the metals may be in the form of alloys, blends, and/orother combinations.

Porous metal sorbent materials comprising Group VIII metals have beendetermined to be chemically compatible with low vapor pressure fluids,such as for example, ClF₃, WF₆, HF, GeF₄, and Br₂, etc.

It has been discovered that, unexpectedly, the porous Group VIII and IBmetal sorbents of the present invention reversibly interact with the lowvapor pressure fluids to sorptively retain the low vapor pressure fluidsand to readily desorb the sorbate fluid under dispensing conditions,such as may involve for example pressure differential-mediateddesorption, thermally-mediated desorption, concentrationdifferential-mediated desorption, etc.

The porous Group VIII and/or IB metal sorbents of the present inventionin one aspect provide a solid-phase metal adsorbent medium for storingand dispensing a low vapor pressure fluid. When used for such purpose,the solid-phase adsorbent medium is preferably characterized by (1) anaverage pore diameter in a range of from about 0.5 nm to about 2 nm and(2) a porosity in a range of from about 10% to about 30%.

The porous Group VIII and/or IB metal sorbents of the present inventionin another aspect provide a protective sorbent medium for immobilizingliquefied gas and preventing ingress of such liquefied gas to theregulator element in an internal regulator-based fluid storage anddispensing system as described in U.S. Pat. No. 6,089,027 for “Fluidstorage and dispensing system,” issued Jul. 18, 2000 to Luping Wang andGlenn M. Tom, the disclosure of which is incorporated by referenceherein. When used for such purpose, the solid-phase sorbent medium ispreferably characterized by (1) an average pore diameter in a range offrom about 0.25 μm to about 500 μm and (2) a porosity in a range of fromabout 15% to about 95%.

The solid phase sorbent medium of the invention is a porous metal matrixcomprising at least one Group VIII metal, Group IB metal or metal alloy,e.g., iron, nickel, cobalt, ruthenium, rhodium, palladium, osmium,iridium, platinum, copper, silver, gold and alloys, blends andcombinations of one or more of the foregoing metal species. The porousmetal matrix is selected to be chemically compatible with the low vaporpressure fluid, such as for example ClF₃, WF₆, HF, GeF₄, Br₂, or thelike, and to accommodate the adsorption and desolption of the fluidwithout adverse reaction or other interaction. Nickel, iron andstainless steel are highly preferred porous metal matrix materials ofconstruction.

The solid-phase adsorbent may be in any suitable shape or conformation,including spherical particles, cylindrical particles, powders, granules,flakes, sheets, or other geometrically regular or irregular forms. Theparticulate or divided form adsorbent may be contained in the fluidstorage and dispensing vessel in a bed or fixed mass, as appropriate tothe fluid and its end use application.

The solid-phase metal adsorbent comprising the porous Group VIII and/orIB metal matrix may also contain non-metal adsorbent particles dispersedin the solid-phase adsorbent composition. Alternatively, the solid-phasemetal adsorbent may be constituted with non-metal adsorbent particlesthat are coated with Group VIII and/or IB metal(s) or metal alloy(s).The non-metal adsorbent particles for such purpose can be formed ofzeolites, carbon materials, porous silicon, polymers, aluminumphosphosilicate, clays, or combinations of two or more of such species,with zeolites and/or carbon materials being preferred. The average sizeof the non-metal adsorbent particles is preferably in the range of fromabout 1000 μm to about 10 μnm.

The porous metal matrix may be formed from fine metal particles, e.g.,having an average particle size in the range from about 1000 μm to about20 nm of Group VIII or IB metals that are sintered, e.g., in a sinteringfurnace at a temperature in a range of from about 20° C. to about 1500°C., to form the porous metal matrix. The sintering operation should beclosely controlled, e.g., by thermal monitoring elements and temperaturecontrollers, to provide a sintered product retaining good porositycharacteristics. Excessive temperatures in the sintering operation willresult in occlusion and closure of the porosity in the matrix structure,and appropriate sintering temperatures and exposure times may be readilyempirically determined for a given application of the invention.

In an alternative synthesis technique, porous metal matrix sorbentmaterials in accordance with the invention can be manufactured byforming a solid-phase matrix of the Group VIII or IB metal or metalalloy, and an oxidizable carbon-containing material. This solid-phasematrix then is heated in the presence of an oxidizing agent to gasifythe oxidizable carbon-containing material. The oxidizablecarbon-containing material may be of any suitable type, such aselemental carbon materials (graphite, diamond, amorphous carbon, etc.)or any of various hydrocarbon compounds. The oxidizing agent can containelemental oxygen, oxygen gas (O₂), ozone, air, or combinations of suchmaterials.

In another variant synthesis technique, the porous metal matrix ismanufactured by forming a solid-phase matrix including the Group VIIImetal and soluble metal oxide particles, and then immersing thesolid-phase matrix in an acidic solution capable of dissolving the metaloxide particles. Preferably, the soluble metal oxide particles areformed of a metal such as Fe, Ni, Ag, or Pt, of suitable particle sizeand particle size distribution characteristics, e.g., having an averageparticle size in a range of from about 0.5 nm to about 2.0 nm.

The porous metal matrix adsorbents of the invention can be usefullyemployed in an adsorption-desorption apparatus for storage anddispensing of a low vapor pressure fluid, including a storage anddispensing vessel holding the adsorbent at an interior gas pressure, andthe vessel coupled to a dispensing assembly arranged to dispensedesorbed low vapor pressure fluid from the vessel in dispensingoperation.

Adsorption-desorption apparatus of a general type in which the porousmetal matrix adsorbents of the invention can be usefully employed, aredescribed in U.S. Pat. No. 5,518,528 for “Storage and delivery systemfor gaseous hydride, halide, and organometallic group V compounds,”issued May 21, 1996 to Glenn M. Tom and James V. McManus.

The porous metal matrix of the invention can also be utilized in aregulator-based storage and dispensing systems of a type described inU.S. Pat. No. No. 6,089,027 for “Fluid storage and dispensing system,”issued Jul. 18, 2000 to Luping Wang and Glenn M. Tom, for protection ofthe regulator element. In such application, the porous metal matrixadsorbent can be deployed in a fluid inlet passage coupled to the fluidregulator, e.g., in a flow-through compartment of such passagecontaining a solid-phase metal sorbent medium formed of the porous metalmatrix, whereby the metal sorbent medium sorptively immobilizes any lowvapor pressure liquefied gas and prevents such from entering the fluidinlet passage from the bulk liquid volume in the vessel, to therebyprotect the regulator from pressure perturbations.

Fluid storage and dispensing systems of the above-described types may beusefully employed for supplying low vapor pressure fluid reagent, byloading the porous metal adsorbent in the storage and dispensing vesselwith the low vapor pressure fluid reagent. The porous metal adsorbent,having a sorptive affinity for the low vapor pressure fluid, physicallyadsorbs the fluid.

At the conclusion of the sorption, when the porous metal adsorbent hasbeen loaded with the fluid and all thermal (heat of sorption) effectshave dissipated, an interior gas pressure obtains in the interior volumeof the vessel. The porous metal adsorbent of the invention enablessub-atmospheric pressure to be maintained in the vessel, to maximize thesafety of the contained fluid system. In subsequent use, fluid isdesorbed from the metal adsorbent and dispensed from the vessel.

Desorption may be effected in any suitable manner, e.g., by heating ofthe porous metal adsorbent to effect desorption of the fluid speciesfrom the adsorbent, or by establishing a pressure differential thatcauses the fluid to desorb from the adsorbent, e.g., application ofvacuum or suction to the interior volume of the vessel through theassociated dispensing assembly of the vessel to desorptively extract thesorbed fluid from the adsorbent, or by flowing a carrier gas through thevessel in order to create a concentration differential, and effectdesorption of the fluid from the adsorbent by the associated masstransfer gradient, so that the fluid is released from the adsorbent andentrained in the carrier gas stream, for discharge from the vessel.

Alternatively, two or more of the above-described modes may be appliedto effect desorption of the fluid from the porous metal adsorbent.Further, any other method of desorption may be employed, as efficaciousto produce disengagement of the adsorbed fluid species from the metaladsorbent.

Referring now to the drawings, FIG. 1 is a schematic representation of astorage and dispensing system 10 comprising storage and dispensingvessel 12. The storage and dispensing vessel may for example comprise aconventional gas cylinder container of elongate character, or othervessel of desired size and shape characteristics. In the interior volumeof such vessel is disposed a bed 14 of the porous metal adsorbent 16 ofthe present invention.

The vessel 12 is provided at its upper end with a conventional cylinderhead fluid dispensing assembly 18 coupled with the main body of thecylinder 12 at the port 19. Port 19 allows fluid flow from the interiorvolume 11 of the cylinder into the dispensing assembly 18. To prevententrainment of particulate solids in the fluid being dispensed from thecylinder, the port 19 may be provided with a frit or other filter meanstherein.

The vessel 12 may also be provided with internal or external heatingelements (not shown) that serve to thermally assist desorption of thesorbate fluid. Preferably, however, the sorbate fluid is at leastpartially, and most preferably fully, dispensed from the storage anddispensing vessel containing the adsorbed fluid by pressuredifferential-mediated desorption. Such pressure differential may beestablished by flow communication between the storage and dispensingvessel, on the one hand, and the exterior dispensing environment orlocus of use, on the other. The dispensing means for the vessel mayinclude pumps, blowers, fans, eductors, ejectors, etc., or any othermotive driver for flowing the fluid from the vessel to the locus of useof the dispensed fluid.

The adsorbent 16 comprises a porous metal matrix including at least oneGroup VIII or IB metal or metal alloy, having sorptive affinity for thelow vapor pressure fluid to be stored and subsequently dispensed fromthe vessel 12, with the sorbate fluid being suitably desorbable from theadsorbent. Such adsorbent 16 is preferably characterized by (1) anaverage pore diameter in a range of from about 0.5 nm to about 2.0 nmand (2) a porosity in a range of from about 10% to about 30%. The poresize distribution of such adsorbent 16 is preferably characterized byabout 80% to about 90% of pores having a diameter in a range of fromabout 1.5 nm to about 2.0 nm, and about 10% to about 20% of pores havinga diameter greater than 2 nm.

The adsorbent may be suitably processed or treated to ensure that it isdevoid of trace components that may deleteriously affect the performanceof the fluid storage and dispensing system.

The adsorbent may be provided in the form of particles, granules,extrudates, powders, cloth, web materials, honeycomb or other monolithicforms, composites, or other suitable conformations.

Although it generally is preferred to operate solely by pressuredifferential at ambient temperature conditions, in respect of thesorption and desorption of the gas to be subsequently dispensed, thestorage and dispensing system may in some instances advantageouslyemploy a heater operatively arranged in relation to the storage anddispensing vessel for selective heating of the adsorbent, to effectthermally-enhanced desorption of the sorbed fluid from the solid-phaseadsorbent.

The fluid storage and dispensing system optionally may be constructedwith the adsorbent being present in the storage and dispensing vesseltogether with a chemisorbent material having a chemisorptive affinityfor contaminants of the sorbate fluid therein.

The fluid storage and dispensing system of the type shown in FIG. 1 isadvantageously employed for the delivery of low vapor pressure fluids ina wide variety of applications, e.g., to carry out various unitoperations of semiconductor manufacturing processes.

FIG. 2 is a schematic cross-sectional elevation view of a fluid storageand dispensing system 300 comprising a sorbent medium 135 formed of aporous metal matrix, according to one embodiment of the presentinvention. The system 300 includes a fluid storage and dispensing vessel302 of generally cylindrical form, with cylindrical side wall 304 closedat its lower end by floor member 306. At the upper end of the vessel isa neck 308 including a cylindrical collar 310 definingg andcircumscribing a top opening of the vessel. The vessel wall, floormember and neck thereby enclose an interior volume 328 as shown.

The interior volume contains a low vapor pressure liquefied gas 200,with the portion of the interior volume 328 that is above the liquid 200containing the corresponding gas 220 derived from the liquid 200.

At the neck of the vessel, a threaded plug 312 of the valve headassembly 314 is threadably engaged with the interior threaded opening ofthe collar 310. The valve head assembly 314 includes a central fluidflow passage 320 joined in fluid flow communication with a centralworking volume cavity in the valve head assembly. The central workingvolume cavity is in turn joined to outlet 324, which may be exteriorlythreaded or otherwise constructed for attachment of a connector andassociated piping, conduit, etc. thereto.

Disposed in the central working volume cavity is a valve element 322that is joined to a hand wheel 326 in the embodiment shown, but mayalternatively be joined to an automatic valve actuator or othercontroller or actuating means.

The valve head assembly 314 also features in the valve block a vent flowpassage 316 joined to an over-pressure relief valve 318 andcommunicating with the interior volume 328 of the vessel, for relief ofgross over-pressure conditions in the vessel.

The central fluid flow passage 320 in the valve head assembly 314 isjoined at its lower end to a connector flow tube 330, to which in turnis joined to the regulator 332. The regulator is set to maintain aselected pressure of the fluid discharged from the vessel, i.e., the gasderiving from the liquid 200. At the lower end of the regulator isjoined a gas inlet tube 336 which in turn is joined, e.g., by buttwelding, to a diffuser unit 134 having a diffuser end cap 131 at itslower extremity. The diffuser unit may be formed of stainless steel,with the diffuser wall being formed of a sintered stainless steel suchas 316L stainless steel. The diffuser unit has a wall porosity thatpermits removal of all particles greater than a predetermined diameter,e.g., greater than 0.003 micrometers at 30 standard liters per minuteflow rate of gas from the system. Filter diffuser units of such type arecommercially available from Millipore Corporation (Bedford, Mass.) underthe trademark WAFERGARD.

In the intermediate portion of the bore of the gas inlet tube 336 isdisposed a bed of the porous metal sorbent 135 of the present inventiondisposed between two foraminous retention elements 137 and 139, whichmay for example comprise disk-shaped screen or mesh elements that aresecured to the inner wall surface of the gas inlet tube 336 and retainthe metal sorbent 135 in position. The porous metal matrix sorbent ofthe present invention is selected to have a suitably high sorptiveaffinity for the low vapor pressure liquid 200 in contact therewithunder conditions obtaining in the interior volume of the vessel 302. Bysuch provision, the sorbent is presented to sorptively immobilize anyliquid 200 that could otherwise, in the absence of the adsorbent, flowinto the regulator 332 and interfere with its proper operation.

In use, the low vapor pressure liquid 200 is contained in the interiorvolume 328 of the vessel 302. The fluid pressure regulator 332 is set toa selected set point to provide flow of dispensed gas when the valve inthe valve head assembly 314 is opened, with the gas flowing through thediffuser unit 334, gas inlet tube 336 (and adsorbent bed 135 therein),regulator 332, connector flow tube 330, central fluid flow passage 320in the valve head assembly 314, the central working volume cavity, andoutlet 324. The valve head assembly may be joined to other piping,conduits, flow controllers, monitoring means, etc. as may be desirableor required in a given end use application.

The system shown in FIG. 2 thus utilizes the porous metal matrix sorbentof the invention in a guard bed, to thereby prevent liquid access to theinternally disposed regulator in the storage and dispensing vessel.Accordingly, the sorbent in such deployment serves to prophylacticallysorb any influent liquid in the gas inlet tube 336 to avoid theoccurrence of pressure perturbations in the operation of the regulator332, so that the storage and dispensing system is enabled to supply gasat a desired consistent pressure and flow rate.

The system of FIG. 2 may also comprise one or more internal or externalheating elements (not shown) to supply thermal energy to the liquid 200.When liquid 200 evaporates to form the gas 220 for delivery out of thevessel, thermal energy in the liquid 200 reduces significantly as aresult of such evaporation, which in turn causes cooling of the liquid200. Such cooling will lower the evaporation speed and slow down the gasflow from the liquid 200. In order to compensate for such reduction ofthermal energy due to evaporation, internal or external heating elementscan be employed to continuously or periodically supply thermal energy tothe liquid 200. Such heating elements can be dispersed directly withinthe liquid 200, or alternatively, be disposed on the external wall ofthe vessel 302.

The invention will be more fully understood with reference to thefollowing non-limiting examples:

EXAMPLE 1

Tests were conducted to determine the sorbate storage capacities of twoporous metal adsorbent materials. The first adsorbent is formedbysintering INCO® Type 210 nickel powder (commercially available fromInco Limited, Wyckoff, N.J., USA) and the second adsorbent was formedfrom INCOFOAM® porous nickel substrate (commercially available from IncoLimited, Wyckoff, N.J. USA). Eachadsorbent was placed in a 7 m availablefrom Swagelok Company, Solon, Ohio, USA), which was then positioned in ain stainless steel container having an interior volume of 50 ml.

Isopropanol (hereinafter “IPA”) was added to the sorbent. The totalweight of IPA liquid added was recorded, and the container wascontinuously monitored for detection of any IPA liquid dripping. As soonas dripping of liquid from the container was detected, addition of IPAliquid was immediately terminated, and the total weight of IPA liquidpreviously added was recorded. The total weight of the added IPA liquidindicated the IPA capacity of the tested adsorbent.

The test results for the two sorbents respectively formed of Inco Type210 nickel powder and of Incofoam were as follows:

Inco Type 210 Incofoam IPA capacity 26.3 g/50 ml 20 g/50 ml

EXAMPLE 2

Similar tests for adsorbents formed of INCO® Type 210 nickel powder(commercially available from Inco Limited, Wyckoff, N.J., USA) and ofINCOFOAM® porous nickel substrate (commercially available from IncoLimited, Wyckoff, N.J., USA) were conducted to determine the storagecapacities of such adsorbents for Br₂ gas.

INCO ® Type 210 INCOFOAM ® porous nickel powder nickel substrate Br₂holding capacity 27 g/50 ml —

Although the invention has been variously disclosed herein withreference to illustrative embodiments and features, it will beappreciated that the embodiments and features described hereinabove arenot intended to limit the invention, and that other variations,modifications, and other embodiments will suggest themselves to those ofordinary skill in the art. The invention therefore is to be broadlyconstrued, consistent with the claims hereafter set forth.

What is claimed is:
 1. A fluid storage and dispensing system for storageand dispensing of a low vapor pressure fluid, comprising: a storage anddispensing vessel; a solid-phase metal sorbent comprising a porus metalmatrix disposed in said storage and dispensing vessel at an interior gaspressure, wherein said porous metal matrix comprises at least one GroupVIIl metal, Group IB metal, or metal alloy thereof; a low vapor pressurefluid sorbed on the sorbent; and a dispensing assembly coupled in gasflow communication with the storage and dispensing vessel, and arrangedfor dispensing fluid from said vessel.
 2. The fluid storage anddispensing system of claim 1, wherein the low vapor pressure fluid to bestored and dispensed by said system comprises a fluid species selectedfrom the group consisting of chlorine trifluoride (ClF₃), tungstenhexafluoride (WF₆), hydrogen fluoride (HF), germanium tetrafluoride(GeF₄), and bromine (Br₂).
 3. The fluid storage and dispensing system ofclaim 1, wherein the porous metal matrix comprises one or more metalsselected from the group consisting of iron, nickel, cobalt, ruthenium,rhodium, palladium, osmium, iridium, platinum, copper, silver, gold, andalloys thereof.
 4. The fluid storage and dispensing system of claim 1,wherein the porous metal matrix comprises nickel.
 5. The fluid storageand dispensing system of claim 1, wherein the porous metal matrixcomprises stainless steel.
 6. The fluid storage and dispensing system ofclaim 1, wherein the porous metal matrix forms a solid-phase metaladsorbent material and is characterized by an average pore diameter in arange of from about 5 nm to 20 nm.
 7. The fluid storage and dispensingsystem of claim 6, wherein the porous met matrix is furthercharacterized by a porosity in a range of from about 10 to abut 30%based on total volume the porous metal matrix.
 8. The fluid storage anddispensing system of claim 6, wherein the porous metal matrix is furthercharacterized by a pore size distribution, wherein (1) from about 80% toabout 90% of pores have a diameter in a range of from about 1.5 nm toabout 2.0 nm, and (2) from about 1.0% to about 20% of pores have adiameter greater than 2.0 nm.
 9. The fluid storage and dispensing systemof claim 6, wherein the porous metal matrix is comprises non-metaladsorbent particles dispersed therein.
 10. The fluid storage anddispensing system of claim 9, wherein the non-metal adsorbent particlescomprise a material selected from the group consisting of zeolites,carbon materials, porous silicon, polimers, aluminum phosphosilicate,clays, and combinations of two or more species thereof.
 11. The fluidstorage and dispensing system of claim 9, wherein the non-metaladsorbent particles comprises a material selected from the groupconsisting of zeolites, carbon materials, and combinations thereof. 12.The fluid storage and dispensing system of claim 9, wherein thenon-metal adsorbent particles have average pore size in a range of fromabout 0.5 nm to about 50.0 nm.
 13. The fluid storage and dispensingsystem of claim 6, wherein the porous metal matrix further comprisesnon-metal adsorbent particles coated with a Group VIII metal, a Group IBmetal or a metal alloy thereof.
 14. The fluid storage and dispensingsystem of claim 13, wherein the non-metal adsorbent particles comprise amaterial selected from the group consisting of zeolites, carbonmaterials, porous silicon, polymers, aluminum phosphosilicate, clays,and combinations of two or more species thereof.
 15. The fluid storageand dispensing system of claim 13, wherein the non-metal adsorbentparticles are formed of a material selected from the group consisting ofzeolites, carbon materials, and combinations thereof.
 16. The fluidstorage and dispensing system of claim 13, wherein the non-metaladsorbent particles have average pore size in a range of frond about 0.5nm to about 50.0 nm.
 17. The fluid storage and dispensing system ofclaim 1, wherein the porous metal matrix forms a solid-phase metalsorbent medium and is characterized by an average pore diameter in arange of from about 0.25 μm to about 500 μm.
 18. The fluid storage anddispensing system of claim 17, wherein the porous metal matrix isfurther characterized by a porosity in a range of from about 15% toabout 95%, based on total volume of the porous metal matrix.
 19. Anadsorption-desorption apparatus, for storage and dispensing of a lowvapor pressure fluid, said apparatus comprising: a storage anddispensing vessel constructed and arranged for holding a solid-phasemetal adsorbent medium; a solid-phase metal adsorbent medium disposed insaid storage and dispensing vessel at an interior gas pressure, whereinsaid solid-phase adsorbent medium includes a porous metal matrixcomprising at least one Group VIII or Group IB metal; a low vaporpressure fluid adsorbed on said solid-phase adsorbent medium; and adispensing assembly coupled in gas flow communication with the storageand dispensing vessel, and arranged for dispensing from the vessel lowvapor pressure fluid desorbed from the solid-phase metal adsorbentmedium.
 20. The adsorption-desorption apparatus of claim 19, wherein thelow vapor pressure fluid comprises a fluid species selected from thegroup consisting of chlorine trifluoride (ClF₃), tungsten hexafluoride(WF₆), hydrogen fluoride (HF), germanium tetrafluoride (GeF₄), andbromine (Br₂).
 21. The adsorption-desorption apparatus of claim 19,wherein the porous metal matrix comprises one or more metals selectedfrom the group consisting of iron, nickel, cobalt, ruthenium, rhodium,palladium, osmium, iridium, platinum, copper, silver, gold, and alloysthereof.
 22. The adsorption-desorption apparatus of claim 19, whereinthe porous metal matrix comprises nickel.
 23. The adsorption-desorptionapparatus of claim 19, wherein the porous metal matrix comprisesstainless steel.
 24. The adsorption-desorption apparatus of claim 19,wherein the porous metal matrix is characterized by an average porediameter in a range of from about 0.5 nm to about 20 nm.
 25. Theadsorption-desorption apparatus of claim 24, wherein the porous metalmatrix is characterized by Porosity in a range of from about 10% toabout 30% by total volume of such porous metal matrix.
 26. Theadsorption-desorption apparatus of claim 19, further comprisingnon-metal adsorbent particles dispersed in the solid-phase adsorbentmedium.
 27. The adsorption-desorption apparatus of claim 26, wherein thenon-metal adsorbent particles comprise a material selected from thegroup consisting of zeolites, carbon materials, porous silicon,polymers, aluminum phosphosilicate, clays, and combinations of two ormore species thereof.
 28. The adsorption-desorption apparatus of claim26, wherein the non-metal adsorbent particles comprise a materialselected from the group consisting of zeolites, carbon materials, andcombinations thereof.
 29. The adsorption-desorption apparatus of claim26, wherein the non-metal adsorbent particles have average pore size ina range of from about 0.5 nm to about 50.0 nm.
 30. Theadsorption-desorption apparatus of claim 19, further comprisingnon-metal adsorbent particles coated with a Group VIII metal, a Group IBmetal or metal alloy tereof.
 31. The adsorption-desorption apparatus ofclaim 30, wherein the non-metal adsorbent particles comprise a materialselected from the group consisting of zeolites, carbon materials, poroussiicon, polymers, aluminum phoposilicate, clays, and combinations of twoor more species thereof.
 32. The adsorption-desorption apparatus ofclaim 30, wherein the non-metal adsorbent particles comprise a materialselected from the group consisting of zeolites, carbon materials, andcombinations thereof.
 33. The adsorption-desorption apparatus of claim30, wherein the non-metal adsorbent particles have average particle sizein a range of from about 0.5 nm to about 50.0 nm.
 34. A fluid storageand dispensing system, comprising a vessel holding a solid-phase metaladsorbent medium having a low vapor pressure fluid adsorbed thereon,said vessel including a port having dispensing means associatedtherewith for controllably dispensing said low vapor pressure fluiddesorbed from the solid-phase metal adsorbent medium in a dispensingmode of operation of said system, wherein said solid-phase metaladsorbent medium comprises a porous metal matrix containing at least oneGroup VIII or Group IB metal.
 35. The fluid storage and dispensingsystem of claims 34, wherein the porous metal matrix is characterized byan average pore diameter in a range of from about 0.5 nm to about 2.0nm.
 36. The fluid storage and dispensing system of claim 35, wherein theporous metal matrix is further characterized by porosity in a range offrom about 10% to about 30%, based on total volume of said porous metalmatrix.
 37. A fluid storage and dispensing apparatus for storage anddispensing of a low vapor pressure liquefied gas, comprising: a storageand dispensing vessel constructed and arranged for holding a solid-phasemetal sorbent medium; a solid-phases metal sorbent medium disposed insaid storage and dispensing vessel at an interior gas pressure, saidsolid-phase metal sorbent medium comprising a porous metal matrixincluding at least one Group VIII or Group IB metal; a low vaporpressure liquefied gas sorbed by said solid-phase metal sorbent medium;a fluid dispensing assembly coupled in gas flow communication with thestorage and dispensing vessel, and arranged for dispensing from thevessel gas derived from the low vapor pressure liquefied gas; and adouble-stage fluid pressure regulator associated with the fluiddispensing assembly, and arranged to maintain a predetermined pressurein the interior volume of the vessel, wherein the fluid dispensingassembly is selectively actuatable to flow gas, derived from the lowvapor pressure liquefied gas sorbed by said solid-phase metal sorbentmedium, through the double-stage fluid pressure regulator, for dischargeof the gas from the vessel.
 38. A fluid storage and dispensing apparatusof claim 37, wherein the porous metal matrix is characterized by anaverage pore diameter in a range of from about 0.25 μm to about 500 μm.39. A fluid storage and dispensing apparatus of claim 38, wherein theporous metal matrix is further characterized by a porosity in a range offrom about 15% to about 95%, based total volume of the porous metalmatrix.
 40. A fluid storage and dispensing apparatus of claim 37,further comprising one or more heating elements for supplying thermalenergy to the low vapor pressure liquefied gas to compensate for heatloss during evaporation of such low vapor pressure liquefied gas.
 41. Afluid storage and dispensing apparatus of claim 40, wherein said heatingelements are disposed on an external wall of the storage and dispensingvessel, and wherein the solid-phase metal sorbent medium conductsthermal energy supplied by said heating elements to the sorbed low vaporpressure liquefied gas.
 42. A fluid storage arid dispensing system,comprising a storage and dispensing vessel for holding a low vaporpressure liquefied gas therein, a discharged assembly disposed on thevessel for dispensing low vapor pressure liquefied gas therefrom, and agas flow regulator inside the vessel arranged for flow therethrough ofgas deriving from the low vapor pressure liquefied gas, so that gasflows through the regulator prior to flow through the dischargeassembly, with a body of solid-phase metal sorbent arranged in thevessel to sorptively immobilize any low vapor pressure liquefied gasthat would otherwise flow into the regulator, said solid-phase metalsorbent including a porous metal matrix comprising at least one GroupVIII or Group IB metal, wherein the porous metal matrix of saidsolid-phase metal sorbent has an average pore diameter in a range offrom about 0.25 μm to about 500 μm.
 43. The fluid storage and dispensingsystem of claim 42, wherein the regulator is coupled with a gas flowconduit inside the vessel arranged to receive gas deriving from the lowvapor pressure liquefied gas, for flow of said gas through the conduit,the regulator and the discharge assembly, wherein said body ofsolid-phase metal sorbent is provided in said gas flow conduit, forcontacting and sorbing liquid therein.
 44. A fluid storage anddispensing system for storing and dispensing a low vapor pressure fluid,comprising: a storage and dispensing vessel; a solid-phase metalsorbent, wherein the sorbent includes a porous metal matrix disposed insaid storage and dispensing vessel at an interior gas pressure, whereinsaid porous metal matrix comprises a porous Group IB or VIII metal ormetal alloy matrix having an average pore diameter in a range (i) offrom about 0.5 nm to about 2.0 nm, or (ii) of from about 0.25 μm toabout 500 μm; and a dispensing assembly coupled in gas flowcommunication with the storage and dispensing vessel, and arranged fordispensing fluid from said vessel.